What are the simple methods to improve frequency of the RTL?

Hi,

I am using Cyclone V GT board, My RTL needs to have multiple stages and nested if else loops. But I intend to reach a Frequency of 200 MHz.

Currently I have my design running at 140Mhz.

I use a single clock for the module.

What are the main points / solution to keep in mind while improving frequency of the design.